College of Engineering Unit:
Our project involves the design of a chemical plant with a annual capacity of 75,000 metric tons of Propionic Acid to meet demands for the food industry, with a focus on liquid-liquid extraction. In the food industry, propionic acid is primarily used in the preservation of various packaged foods as an antifungal and antibacterial agent to prevent mold and bacterial growth. Additionally, it is also used in the production of flavorings and fragrances, and has many uses outside of the food industry as a chemical intermediate in the production of plastics and pharmaceuticals. Due to the abundance of packaged foods that require preservation, propionic acid is in high demand. The team plans to produce propionic acid in the designed plant through the Reppe process using ethylene, carbon monoxide, and water as reagents. The reaction will be catalyzed using nickel carbonyl. This pathway has a high conversion, a high yield, uses relatively cheap raw materials, as well as a very high atom efficiency since the reaction does not create any byproducts when producing propionic acid.
Separation of crude propionic acid from the aqueous reaction effluent can be done with LLE using a multitude of solvents such as 1-octanol in TOPO. This is beneficial as using liquid-liquid extraction as much as possible reduces the amount of distillation that must be done in order to purify the product. Distillation is very energy intensive, so avoiding or reducing the amount of distillation used is very beneficial. To inform the design of our plant's liquid-liquid extractor, a pilot-scale liquid-liquid extractor from Armfield was used to run experiments on the separation of propionic acid. These experiments found that separation of aqueous propionic acid was very difficult with most common solvents and that a combination of LLE and distillation would be required to achieve the desired separation.
